N-Ethyl-5-phenylisoxazolium-3'-sulfonate

Also known as: Woodward's reagent K, NEPIS, 2-Ethyl-5-phenylisoxazolium-3'-sulphonate, 3-(2-Ethyl-1,2-oxazol-2-ium-5-yl)benzenesulfonate, 2-Ethyl-5-(3-sulfophenyl)isoxazolium inner salt, 3-(2-Ethylisoxazol-5-yl)benzenesulfonic acid

N-Ethyl-5-phenylisoxazolium-3'-sulfonate (CAS 4156-16-5) is a compound in the Organic Acids category listed in the Jingsj chemical database. It has the molecular formula C11H11NO4S and a molecular weight of 253.274 g/mol. Key property: a melting point of 216-219 °C (dec.). It is classified under GHS with signal word Warning and hazard statements H302 — Harmful if swallowed. No supplier offers are currently listed; request a quote. Record last updated Aug 21, 2026.

CAS No.: 4156-16-5
Jingsj CID: J-1050257-5
Molecular Formula: C₁₁H₁₁NO₄S
Molecular Weight: 253.274 g/mol
Category: Organic Acids
Last updated: 8/21/2026

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Physicochemical Properties

Melting Point	216-219 °C (dec.)
Exact Mass	253.040878
PSA	82.60000
LogP	2.23890

GHS Safety & Compliance

IrritantSignal word: Warning

H302 — Harmful if swallowed

Customs & Trade Information

HS Code	2934999090
Summary	2934999090. other heterocyclic compounds. VAT:17.0%. Tax rebate rate:13.0%. . MFN tariff:6.5%. General tariff:20.0%

Frequently Asked Questions

What is the CAS number of N-Ethyl-5-phenylisoxazolium-3'-sulfonate?

The CAS number of N-Ethyl-5-phenylisoxazolium-3'-sulfonate is 4156-16-5.

What are the molecular formula and molecular weight of N-Ethyl-5-phenylisoxazolium-3'-sulfonate?

N-Ethyl-5-phenylisoxazolium-3'-sulfonate has molecular formula C11H11NO4S and molecular weight 253.274 g/mol.

Is N-Ethyl-5-phenylisoxazolium-3'-sulfonate hazardous?

N-Ethyl-5-phenylisoxazolium-3'-sulfonate has GHS signal word Warning and hazard statements H302 — Harmful if swallowed.

Data compiled from public chemical databases such as PubChem and supplier catalogs; supplier offers are provided by suppliers.

Last updated: 8/21/2026

How to cite: Jingsj. "N-Ethyl-5-phenylisoxazolium-3'-sulfonate (CAS 4156-16-5)". Jingsj Chemical Database. https://www.jingsj.com/compound/J-1050257-5 (accessed 2026-11-09).

Data for reference only; verify product details with suppliers before purchase.